hygienetown profile in oral health

by Trisha E. O’Hehir, RDH, MS and Amy Francis, RDH, OM

Abstract Nose and both bring oxygen into the lungs but with different consequences and different oxygen absorption levels. Dental and den- tal hygiene education in the past touched only briefly on problems associated with mouth breathing, primarily dry, inflamed oral tissues around maxillary anterior teeth. There is now evidence that mouth breathing has far more serious and long-lasting implications than drying of oral tissues. A simple five-step screening process identifies factors affecting nasal breathing.

Objectives At the end of this program, participants will be able to: 1. Understand physiologic differences between nasal breath- ing and mouth breathing. 2. Describe symptoms of mouth breathing. 3. Understand the impact of mouth breathing on malocclusion. 4. List the five steps in the mouth-breathing screening exam. 5. Recognize the role of RDHs in preventing mouth breathing.

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Humans are designed to be nose breathers, but for a variety Mouth Breathers are prone to: of reasons the switch can be made to mouth breathing, with seri- ous consequences. The nose and mouth have different func- tions. Each nostril functions independently and synergistically nasal congestion to filter, warm, moisturize, dehumidify and smell the air. It’s like watery, itchy eyes having two noses in one. Breathing through the mouth provides runny nose none of these benefits of nose breathing and a lengthy list of allergies acid reflux adverse effects. The problems associated with mouth breathing begin in the mouth by changing the tongue rest position, thus enlarged tonsils poor palate development changing the normal growth pattern of the palate, both maxil- crooked teeth lary and mandibular jaws and the airway.1 Inadequate skeletal tonsil stones recessive chin growth leads to crowded teeth, a high-vaulted palate and abnor- dry Long Face Syndrome mal occlusion, called the Long Face Syndrome. In mouth speech problems breathers, the tongue rests down and forward, not in the palate sleep disturbances weak, flaccid lips as it should, leading to tongue thrust, abnormal swallowing fatigue fibromyalgia low energy level chronic fatigue syndrome habits and speech problems. A significant problem with mouth ADHD silent aspiration breathing is reduced oxygen absorption leading to a cascade of tongue thrust pneumonia sleep, stamina, energy level and ADHD problems. Dryness of abnormal swallowing habits the oral and pharyngeal tissues from mouth breathing leads to aerophagia bed wetting inflamed tonsils, tonsil stones, dry cough, swollen tongue, hali- frequent urination at night tosis, gingivitis and caries. Mouth breathers chew with their mouths open, swallowing air, leading to gas, bloating, flatulence and burping. Lips become flaccid with mouth breathing because Physiology of Breathing they don’t close regularly to provide the necessary lip seal. The purpose of breathing is to deliver oxygen to the cells Dental and dental hygiene education in the past touched of the body and to remove excess carbon dioxide. The body only briefly on problems associated with mouth breathing, pri- requires approximately two to three percent oxygen and the marily dry, inflamed oral tissues around maxillary anterior teeth. atmospheric level is 21 percent so there is no need to store oxy- Adding to that knowledge, there is now evidence that mouth gen. The body’s requirement for carbon dioxide is 6.5 percent breathing has far more serious and long-lasting implications and the atmospheric content is 0.03 percent, so the body has to than drying of oral tissues. produce and store carbon dioxide in the lungs and blood. Many misconceptions about mouth breathing persist today. Carbon dioxide is produced as a byproduct of exercise and In some circles, mouth breathing and nose breathing are thought digestion of food. Carbon dioxide has several functions in the to be equivalent and in athletics, mouth breathing is still body: facilitate release of oxygen from hemoglobin, trigger assumed to be better than nose breathing. Assuming that mouth breathing, maintain blood pH by buffering with bicarbonate or breathing and nose breathing are no different ignores basic phys- carbonic acid and prevent smooth muscle spasms. All of these iologic facts about the exchange of oxygen and carbon dioxide. functions are reduced or impaired in mouth breathers. Today professional athletic teams are being coached to train with Breathing is subconscious with each inhale determined not their mouths closed, focusing on nose breathing to increase by the need for oxygen, but by the level of carbon dioxide in the endurance, stamina and muscle memory. Another misconcep- alveoli of the lungs and blood. As carbon dioxide builds up in tion is assuming more oxygen is absorbed with a big inhale the body, the pH of the blood drops. This pH change is moni- through the mouth doesn’t take into consideration the fact that tored by chemoreceptors in blood vessels that will signal the oxygen is absorbed on the exhale, not the inhale. Sleep medicine brain to trigger the next breath. Normal respiration follows a writings assume mouth breathing and sleep are not con- gentle wave pattern with 10 to 12 breaths per minute, providing nected, which is not supported by scientific evidence. Mouth five to six liters of air per minute. Mouth breathers often have a breathing and obstructive sleep apnea (OSA) are connected.4 respiration rate above 12 breaths per minute and those with Dental professionals are in a perfect position to evaluate asthma and serious medical conditions have rates of 20 respira- mouth and nose breathing, check for tongue rest position and tions per minute or higher. intervene early with young children to assure normal skeletal Breathing through the nose controls the amount of air taken development and help mouth breathers of all ages become nose in and, more importantly, controls the amount of air exhaled. breathers. Understanding the physiology of breathing and implementing a simple five-step screening system raises aware- 1. Souki, B., Pimenta, G., et al: Prevalence of malocclusion among mouth breathing in children: do expec- tations meet reality? Int J Pediatr Otorhinolaryngol 73(5):767-773, 2009. ness of the significance of this problem and provides an oppor- 4. Juliano, M., Machado, M., et al: Polysomnographic findings are associated with cephalometric measure- tunity to implement far-reaching changes in patients’ lives. ments in mouth-breathing children. J Clin Sleep Med 15(5):554-561, 2009. continued on page 9

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Oxygen is absorbed on the exhale, not on the inhale. The back- mouth. Others believe they are nose breathers, but if you watch pressure created in the lungs with the slower exhale of nose them, their mouth is open most of the time. Sitting still, they breathing compared to mouth breathing allows more time for might have their mouth closed, but if they get up and walk the lungs to transfer oxygen to the blood. The exchange of oxy- across the room, their mouth is open. Telltale signs of mouth gen in the blood requires the presence of carbon dioxide. breathing are an addiction to chap stick or lip balm. An open Approximately 98 percent of oxygen is carried in hemoglobin. mouth leads to drooling, both awake and asleep, causing Carbon dioxide levels need to be at five percent in the alveoli chapped lips and a tendency for mouth breathers to lick their and arterial blood before the oxygen molecules are released from lips frequently. Closed mouth lip seal is efficient at keeping hemoglobin to reach brain and muscle cells. Lower than five saliva in and air out but chronic mouth breathers find it very dif- percent carbon dioxide levels lead to an elevation in blood pH ficult to hold their lips together. Mouth breathing at night and the oxygen “sticks” to the hemoglobin, this is the Bohr causes drooling and dries the oral tissues so the mouth, teeth, Effect, first described in 1904 by physiologist Christian Bohr. tissue and throat are all dry upon waking. If someone wakes Nitric oxide is released in the nasal cavity and inhaled with with a dry mouth, he or she is likely a mouth breather at night, nose breathing. Nitric oxide increases the efficiency of oxygen which means he or she is also mouth breathing during the day. exchange. With nitric oxide, blood oxygen increases by 18 per- The tongue normally rests against the palate, without touch- cent. Mouth breathing bypasses the nitric oxide. ing the teeth. With mouth breathing, the tongue drops down Seventy-five percent of the inhaled oxygen is exhaled. and forward. It might in fact be that the down and forward During strenuous exercise, 25 percent of the oxygen inhaled is tongue position triggers mouth breathing. Mouth breathing is exhaled. Mouth breathing to take in more air does not increase impossible with the tongue resting against the palate. A simple the level of oxygen in the blood, which is already 97-98 percent tool to self-test for mouth breathing is the square plastic bag saturated. Mouth breathing with big breaths actually lowers the closers used on plastic bread bags. Place the square plastic chip carbon dioxide level in the lungs and the blood leading to lower between the lips and have the person go about their daily activ- levels of oxygen released from the hemoglobin to body cells. ities. If the chip falls out, they are mouth breathing. Taking in more air doesn’t deliver more oxygen to the cells of the body. A balanced pH of the blood is achieved with proper oxy- Mouth Breathing – What Goes Wrong gen-carbon dioxide exchange. Nasal breathing will increase oxy- Several things go wrong with mouth breathing, beginning gen in the lungs, blood and cells. Excessive carbon dioxide loss with oxygen/carbon dioxide exchange, the change in tongue rest through mouth breathing decreases oxygen levels in the lungs, position and swallowing air. The low carbon dioxide levels asso- blood and cells. ciated with mouth breathing trigger the activation of breathing faster than usual, leading to over breathing or . Signs of Mouth Breathing With less oxygen being delivered to the brain, muscles and all Determining if someone is a mouth breather is not always the cells of the body, the body functions less than optimally. easy. Some people admit they always breathe through their Sleep is often disturbed and of poor quality, leaving the mouth breather tired in the morning and feel-

» ing fatigued mid-afternoon. Attention- deficit hyperactivity disorder (ADHD) Five-step screening for mouth breathing is also linked to mouth breathing.11 This dryness and lack of air filtration in Lips together at rest – yes or no? mouth breathing causes enlarged and inflamed tonsils and adenoids and Nasal breathing – yes or no? increased risk of upper respiratory tract (check each nostril for air intake) infections. Lower levels of carbon diox- ide cause smooth muscle spasms associ- Tongue posture at rest – up, down, middle? ated with gastric reflux, asthma and bedwetting. Smooth muscle is found throughout the body in the respiratory Frenum length – adequate or tight? (mouth open wide should measure three fingers system, digestive system, circulatory stacked vertically, with the tongue on the roof of the mouth, opening is two fingers. system, all hollow organs and all tubes Less than that indicates a tight lingual frenum.) and ducts. The tongue resting in the palate Palatal width – adequate or narrow? (measure with a cotton roll, cross-arch on the provides passive pressure, stimulating palate between bicuspids.) stem cells located in the palatal suture and within the periodontal ligaments

9 SEPTEMBER 2012 » hygienetown.com hygienetown profile in oral health around all the teeth to direct normal palatal growth. When the breathing for themselves. Be sure they can breathe through their tongue rests in the palate, the teeth erupt around the tongue, nose before taping. Best to test this during the day before trying producing a healthy arch form. The lateral pressures from the it overnight while sleeping. Try the tape yourself before suggest- tongue counters inward forces from the buccinator muscles. ing it to a patient. A variety of oral appliances are available that When the tongue is down and forward, the buccinator muscles position the tongue to the roof of the mouth, close the lips and continue to push unopposed, causing the upper arch to collapse. encourage nose breathing.9 In many cases, the tongue might Children who mouth breath have an underdeveloped, narrow need to be exercised since it’s been laying on the floor of the maxilla with a high vault.2 They develop a retrognathic mouth and doesn’t have the stamina to rest on the palate all day mandible and generally have a long face. Harvold et al. surgi- or all night. Orofacial myofunctional exercises are important at cally blocked noses in monkeys and they all developed maloc- this stage. These exercises are essential for those receiving a clusions from mouth breathing.3 Mouth-breathing-related frenectomy to treat ankylosglossia. In adult cases of life-long problems of skeletal development will set children up for mouth breathing, orthodontics to expand the palate may be nec- obstructive sleep apnea later in life.4 essary to make room for the tongue.10 It might seem logical that mouth breathing occurs because Screening for mouth breathing is easy and takes very little the nose is congested, but that is not always the case. The brain time with the five-step process. The first three steps are easily of a mouth breather thinks carbon dioxide is being lost too answered with observation and questions to the patient. First, quickly from the nose and stimulates the goblet cells to produce are the lips together, second, can the person breathe through mucous in the nose to slow the breathing.5 This creates a viscous their nose and third, where is their tongue at rest? The next two circle of mouth breathing triggering mucous formation, nasal steps require measurement, first the mouth opening and second passage blocking, leading to more mouth breathing. So in fact, the mouth open with the tongue touching the roof of the mouth breathing can cause nasal congestion leading to more mouth. Most people can open the width of three fingers stacked mouth breathing. vertically. With the tongue on the roof of the mouth, they In some cases, mouth breathing is caused by ankyloglossia, should be able to open at least two fingers. Less than that and or a tight lingual frenum keeping the tongue from effectively there is a problem with the lingual frenum, either ankyglossia or moving in the mouth to assist in chewing and swallowing and a tight lingual frenum. The last screening step is to measure the comfortably resting on the palate.6 Unless a frenectomy is done, maxillary cross arch distance between the bicuspids. The dis- mouth breathing will continue. Ankyloglossia can be diagnosed tance should be equal to a standard cotton roll. and treated in the first few days after birth.7 However, many The earlier mouth breathing is recognized and converted to cases are ignored until significant problems have developed. nose breathing, the fewer and less serious the problems will be. Early intervention prevents subsequent problems.8 Dental hygienists are the ideal dental professionals to screen for mouth breathing. Despite the fact that people are more often Changing from Mouth to Nose Breathing asked to open their mouths in a dental office, checking for a Bringing a person’s mouth breathing to his or her attention closed mouth is essential to oral and general health. starts the process of breaking the habit. Some people will change back to nose breathing when made aware of it. To remind peo- ple to keep their lips together, paper tape is often used by Author Bios breathing coaches. It may sound strange, but easy-to-remove paper tape helps people experience the many benefits of nose Trisha O’Hehir is currently the Editorial Director for Hygienetown.com and Perio Reports. She received her 2. Malhorta, S., Pandey, R., et al: The effect of mouth breathing on dentofacial morphology of growing child. J Indian Soc Pedo Prev Dent 30(1):27-31, 2012. education at the University of Minnesota and her four- 3. Harvold, E., Tomer, B., Vargervik, K., Chierici, G.: Primate experiments on oral respiration. Am J decade career has included roles as clinician in the USA and Zurich, Orthod 79(4):359-372, 1981. Switzerland, faculty at the Universities of Minnesota, Washington, 5. Bresolin, N., Shapiro, P., et al. Mouth breathing in allergic children: it’s relationship to dentofacial devel- opment. Am J Orthod 83 (4):334-340, 1983. Arizona and Louisville, international speaker, writer, instrument 6. Olivi, G., Signore, A., Olivi, M., Genovese, M.: Lingual frenectomy: functional evaluation and new designer, inventor and entrepreneur. therapeutical approach. Eur J Paediatr Dent 13: 101-106, 2012. 7. Fiorotti, R., Bertolini, M, Nicola, J., Nicola, E.: Early lingual frenectomy assisted by CO2 laser helps Amy Francis prevention and treatment of functional alterations caused by ankyloglossia. Int J Orofacial Myology 30: is both a dental hygienist and an orofacial 64-71, 2004. myologist, teaching people how to breath, chew and swal- 8. Suter, V., Bornstein, M.: Ankyloglossia: facts and myths in diagnosis and treatment. J Perio 80: 1204- low. Amy was working in clinical practice when she went on 1219, 2009. 9. Cartwright, R., et al. Snoring Control Using a New Tongue-Retaining Oral Appliance” Journal of Sleep, for more training by completing her orofacial myology cer- Vol. 27, 2004, 412. tification program in 2010 in Los Angeles. Amy spoke at the 10. Singh, G., Lipka, G.: Case Report: introducing the wireframe DNA appliance. J Am Acad Gnathol 2011 Townie Meeting on the importance of nose breathing. Ortho 26(4): 8-11, 2009. 11. Bonuck, K., Freeman, K., Chervin, R., Xu, L.: Sleep-disordered breathing in a population-based cohort: Amy lives and works in Lake Havasu, Arizona. behavioral outcomes at 4 and 7 years. Pediatrics 129(4): e857-e865, 2012.

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